Lung cancer is the most common cause of death due to oncological disease in the world: 1.37 million deaths per year. In Spain, 30,000 cases are detected annually and 23,000 people die from this cause, according to the Spanish Society of Pulmonology and Thoracic Surgery (Separ). Survival is less than 15% five years after diagnosis. The high mortality rate is due to the fact that at the time of diagnosis the disease is in an advanced phase in 70% of cases. Symptoms usually appear late and surgery, the treatment that provides the highest cure rates, is only indicated in the initial stages of the disease.
Early diagnosis is the key to increasing survival in lung cancer. It is achieved through low-dose computed tomography (LDCT), a test that allows the tumor to be identified at an earlier stage when it forms small nodules in the lung before spreading to other areas of the body. In this sense, at the end of 2022 the European Commission updated its recommendation for cancer screening. In addition to the early detection of breast, colorectal and cervical cancer, screening for lung, prostate and gastric cancer was incorporated. The EC urges states to incorporate screening in a phased manner starting in 2025.
Scientific societies, patient associations and foundations consider that CT screening at low doses of radiation only for risk groups would constitute a paradigm shift in the situation of lung cancer. In general, smokers or former smokers – those who have quit tobacco less than 15 years ago – between 55 and 74 years old are considered at risk.
However, a report commissioned by the Ministry of Health from the Canarian Health Service and the Galician Agency for Knowledge Management in Health has cooled expectations, alluding to the high cost of screening in relation to its possible benefits, the difficulty in identify the target population or the risk of false positives or overdiagnoses. “The balance between the benefits and risks of lung cancer screening with BDCT is complex, due in part to the great heterogeneity and lack of consensus on essential aspects of the process,” he says.
Juan Carlos Trujillo, clinical head of thoracic surgery at the Sant Pau hospital, relativizes the economic arguments of the report – each CT scan, which generally each person should perform annually and for the 15 years following abstinence, costs between 60 and 80 euros. and disagrees about the supposed difficulty in identifying the target population: “There is a risk factor that marks a much higher probability of cancer, which is tobacco. We have a population that must be attacked. Also, the older you are, the greater the probability. We already have two characteristics that allow us to narrow down the population. Although age and smoking are not perfect variables, they do allow us to make a first selection, a risk model to achieve a more precise screening. Breast cancer detection is not perfect either: it only discriminates against age and sex, you are also leaving out other people.”
Two large studies support the benefits of screening. In the United States, the NLST showed that screening through diagnostic imaging reduced mortality from lung cancer by 20% in people with a history of smoking, while the European Nelson research estimated this reduction at 26%.
But approximately 50% of individuals who develop lung cancer do not meet the criteria currently used to access a screening program. Around 15% of those affected have not smoked and there is a significant percentage of patients under 20 years of age, for example.
Luis Seijo, pulmonologist at the Clínica Universidad de Navarra and coordinator of the Thoracic Oncology area at Separ, is the only Spanish participant in the Solace project, a consortium formed by 33 European institutions dedicated to the implementation of screening in Europe and the study of its feasibility, cost benefit. “No one hesitates to spend money on an immunotherapy treatment that costs up to 400,000 euros. Are we willing to spend on treatments and not on prevention? Where do we set the limits, who sets them? ”He questions regarding the report commissioned by the Ministry of Health.
According to Seijo, the evidence of the benefit of screening, as well as the consensus of the scientific community, is unquestionable. But we must continue to tighten the circle of the candidates. The more tests, the higher the economic cost, the lower the detection rate and, probably, the more false positives. “We have to continue investigating, to find out why a person who has smoked a lot has not developed lung cancer and another who has never smoked has. "If we manage to find some marker in the blood regarding the risk of developing the disease, it should enter the detection program, even if it does not correspond to the age and smoking criteria."
Seijo does not doubt that, sooner or later, screening will be incorporated into the portfolio of social security services (and will not, in his experience, cause smokers to continue smoking for the certainty that the tumor will be detected in time). “The United States is doing it,” he says. Europe proposes it, our neighboring countries are carrying out ambitious experiments. I don't know when it will be, but I want it to be as soon as possible because it is something I have been doing for 20 years and I have seen the benefit it entails and the little harm it causes to individuals who have some discovery that is not important."
Trujillo and Seijo co-direct the Cassandra lung cancer screening project that will be launched imminently in 20 hospitals in fourteen autonomous regions.
